EDIT: Maybe this should be moved to the programming section. I put it here because it was targetted at RS-servers.

Requirements:

Any IDE: I'll be using intelliJ, because it's better (imo).

A commented source: People who don't comment their sources shouldn't do releases. I'll be using Kethsi, as it was the first one I found with comments.

How to:Step one:
Load your project into the IDE.
Basically, just click import and click next.

Step two:
Find the "Generate JavaDoc" menu item. In intelliJ it will be under the menu-bar "tools".

Step three:
Choose a folder to generate the output to. I recommend you making a folder in your project.

Step four:
Now you can navigate to your JavaDoc, choose the index.html file, open it in a web-browser and take a look at it.

Why would I want to do this?

It'll give you an overviewable interface to navigate through your code - hence making it easier to find what you're looking for.

If you're going through somebodies elses code, it'll be normal that you don't really know what it's doing. Here you can easily go through every class, packages and get yourself a better understanding of the already implemented methods.

If you perhaps want to offer plugins for your clients, you could create public methods that will make up the "API" for the plugins.

Readabiltity

You can write code for a server without having access to the source code details.